shipit: precompile manifest and disable compilation fallback #1794

Job	Run time
benchmark-default (truffleruby, --excludes=knucleotide,lobsters,ruby-lsp,shipit)	13m 5s
test (ruby)	51s
benchmark-graph	51s
benchmark-default (ruby)	11m 24s
benchmark-ractor-only (head)	39s
test (head)	52s
test (truffleruby)	1m 51s
benchmark-default (head)	12m 20s
benchmark-run-once	1m 39s
benchmark-ractor (head)	6m 39s
all-tests	2s
	50m 13s

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